Straw incorporation boosts soil health according to farmers

Straw incorporation was the focus of this year’s Irish Tillage and Land Use Society (ITLUS) summer conference.

The event was held online which allowed three farms to be visited virtually.

The farmers concerned were John Monohan of Co. Carlow, Walter Furlong of Co. Wexford and John O’Neil of Co. Waterford. All three have been incorporating straw for at least 15 years with the first two using minimum till and the latter still relying on the plough.

Whichever cultivation technique was used, all three agreed that there was a definite increase in soil health over the years,

Indeed, the general consensus was that it was not an overnight fix; the full effect took time to materialise and it is worth waiting for.

However, each of them had a different story to tell of their experience in introducing and managing the practice.

Yet a few common themes did emerge: a noticeable rise in earthworm activity; an increase in potassium levels; and improved drainage being three major benefits.

John Monohan

John Monohan noted that patterns of different growth rates appearing in the fields when he first switched over, gave some cause for concern to begin with.

However, these had disappeared by the following summer and yield didn’t appear to be affected.

He believes that earthworm activity was the cause and happily noted that there now appears to be a greater proportion of the larger species which burrow deeper.

Nitrogen lock up was also a worry at first, but again, with time, that concern also faded. Within three or four years he began to notice that the ground had ‘freed up’ and the tractor was being given a much easier time when cultivating.

John O’Neil

John O’Neil of of Co. Waterford took to straw incorporation because being a long way from any major roads, his market for bales was limited. He has been at it for at least 22 years and discs the soil before ploughing.

He attaches great importance to discing and pressing the stubble after the combine has taken the crop and chopped the straw. All three farmers agreed that the degree of soil contact with the straw is of far more importance than chop length, hence John O’Neil’s enthusiasm for the roller attached to his discs.

A 50% breakdown of the straw is quite possible within three weeks if the stubble is pressed he noted. Despite the plough, he also reports that worm activity has increased and soil structure is greatly improved.

Water retention in drought years, as well as better drainage when wet, are other factors that he feels have helped with improved yields over the years.

Walter Furlong

The land that Walter Furlong now farms in Wexford has been under a min-till, with straw incorporation regime since 2001. This was taken a step further in 2006 with the introduction of cover crops, which, Walter claims, have increased soil organic matter by a healthy 636kg/ha on average.

What is important with cover crops, is that there is good seed to soil contact; it must be treated and managed as a second crop to get the best results he noted. The results achieved so far include a significant decrease in fertiliser use, much less diesel consumed, as well as better soil health and increased yields.

With this amount of carbon sequestration Walter believes that selling on carbon credits may well become another income stream for farmers.

Slugs are rarely an issue

One of the concerns often expressed about straw incorporation is the problem of slugs.

Yet it would appear that this could be avoided if the straw was mixed in well with the soil, as this slows their spread and allows the crops to grow away from them.

Straw incorporation Measure (SIM)

A further presentation was given by Michael Maloney of the Department of Agriculture, Food and the Marine (DAFM) on the current status and requirements of the Straw Incorporation Measure.

He noted that this is the first year of the measure and was pleased to say that there had been around a 90% uptake of the €10 million available.

He also pointed out that it was first and foremost a support measure for tillage farmers, as well as being a method to encourage carbon sequestration.

The average area for each application was around 20ha and the average payment will be €4,546.

He also presented the following breakdown of the grant applications, adding that he expected some minor fluctuations up until the scheme closed completely on June 12.

As to the question of what actually constitutes incorporation he replied that presently the department does not prescribe a minimum depth, yet the scheme will be reviewed over the winter, so there may be changes.

He was also encouraged by the the degree of take-up by farmers; this will help justify the continuation of the scheme into the future, although he could not say for how long.